It is well known to include images in web pages. The standard way of doing this is to include an html link in the web page. An example of such a link is:
<img src=“/images/diagram_small.jpg” width=“295” height=“235”  alt=“eMailSignature consists of three components” />Here, the tag “img src” specifies the location of the image to be retrieved, which is a file “diagram_small.jpg” conforming to the JPEG image encoding standard. The file is located in the directory “/images/”, while the full http address of the file can be determined from information provided in the remainder of the web page. The “alt” tag specifies some wording for the browser to display as an alternative to the image, for example, if the image cannot be successfully retrieved or displayed. The “width” and “height” tags specify the size of a rectangular box or window within which the image is to be displayed. Assuming a rectangular image, the image will generally be displayed so as to fill its display window.
As part of displaying or rendering a web page including the above html code, a browser accesses the location specified by the “img src” tag to retrieve the file containing the image data. The browser then determines the best location for presenting the image within the rendered page. This location can be selected having regard to the size of the image, the size of the screen used for the current display, etc.
In the operation of a standard browser, if a user right-clicks over the image, the user is presented with a menu of options relating to the image. For example, a user may be able to print the image, save the image as a file—i.e. a local duplicate of “diagram_small.jpg”, copy the image into another application, and so on. However, such a facility may be undesirable for the provider of the web content, for example, if the image is subject to copyright restrictions or is otherwise considered to be valuable intellectual property. Likewise, many people upload various images onto social networking sites such as Facebook for sharing with friends. However, a user may prefer that his or her images are only available for viewing on this site, without allowing other people to easily download and copy such images.